Romans 3:3-4 (NLT)
[sup]3[/sup] True, some of them were unfaithful; but just because they were unfaithful, does that mean God will be unfaithful? [sup]4[/sup] Of course not! Even if everyone else is a liar, God is true. As the Scriptures say about him,
“You will be proved right in what you say,
and you will win your case in court.”
OP, you misunderstand scripture. The verse in question is a reference to Psalm 51:4...
[sup]4[/sup] Against you, and you alone, have I sinned;
I have done what is evil in your sight.
You will be proved right in what you say,
and your judgment against me is just.
Thse scriptures are hailing the perfect righteousness of God and His perfect, undefiled spoken word and just judgment concerning everything about us. By comparison, man's rightful speech and his word is useless.